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MG MGB Technical - Mk1 roadster seat belts

Has anyone fitted inertia reels to the mounting point on the rear wheel arch - this is the forward one as pictured, not the later one right at the back.

Type used? Any issues? Or does it have to be statics on these?

Paul Hunt

Paul - I have no experience with shoulder belts in the MKI roadster, but have read that the shoulder belt needs to be at least the average height of the person's shoulder to prevent injury (for that reason, I gave up on the idea of shoulder belts in our 66 MGB). Cheers - Dave
D W DuBois

Paul I made these reel mounts for my 1969 roadster to keep the reels up, this was to allow room to stow my pack away hood, A.T

andy tilney

They fit there physically, the Securon type adjust for any angle so work fine.

However as has been mentioned, if the belt point is lower than the shoulder height, the spine will undergo compression forces on impact and can be more damaging than the crash itself. This is why the popular place to have them is on top of the arch for GT cars and on the rear pannel between the cockpit rail and the bootlid for tourers, only a few models had the captive fixings and reinforcement though.

Without making things annoying, fabricating a bracket as Andy has will be perhaps the least dangerous way to go.
The belts as they are now will be almost as dangerous as inertia reel would be, i'd probably rather just wear a lap belt and hope my guts could take the forces.

Safety fast and all that!
Roadwarrior

Thanks. The compression forces would apply to statics and inertia reels, I suppose that's why they moved the statics to the external panel just behind the cockpit rail and the GTs to the top of the arch. Although why my 73 roadster has the boss at the lower rear corner where the rear bulkhead meets the battery shelf, and the 75 V8 has them in the early forward position I don't know.

Were lap belts legal once fitment became compulsory? From what I've read this was about when this car was built/registered, I don't know which side it falls.
Paul Hunt

Motorsport requirements here specify between 10 and 45 deg down from horizontal. Haven't checked whether these are NZ specific or international standard, but most safety-critcal items are the latter. Given the higher impacts poetentiall involved, it goves a good guide to what's sensible.

Paul, the main convern I have had with Mk1 mountings I've seen is that some people use only one of the two studs per side. To me, there's not enough strength in that, and a better approach is a plate secured to both, with the inertial belt secured to th plate.

And as per Roadwarrior, Securon does the job well there with the ability to adjust in two planes.

Paul Walbran

This might help with seatbelt law regarding fitment requirements.

http://www.motuk.co.uk/manual_510.htm
Roadwarrior

"people use only one of the two studs per side"

Two studs? Where ever they are I've only ever seen one - on the arch that is. Pictures of two? And studs? I've only ever seen threaded bosses to take bolts - arch, sill and tunnel.
Paul Hunt

Early Spridgets had two studs on the wheelarch.

I haven't seen enough early Bs to know if they had the same.
Dave O'Neill 2

http://4.bp.blogspot.com/-MIf2MANf07Q/T2ubZ3-BeVI/AAAAAAAABSk/vO4mrprsFzw/s1600/IMG_7091.JPG

That's the Spriget set up on early cars. Some people just attach to one as mentioned.

http://www2.mg-cars.org.uk/images/bbs/posts/71_0_61548582201086_1200270898.jpg

That's the very very early MGB provision for a seat belt. A very similar 2 bolt affair in a different place.
Again, some people like to just use 1 stud.
Roadwarrior

It was the set-up on my 63 B, GHN3 14307, I'm not sure when the change to the now-conventional single 7/16 UNGanchorage occurred.
The point about using only one of the two studs is that they are only 5/16" ... in combined shear they have the same cross-sectional area as a single 7/16", so if using only one 5/16" you have only half the anchorage strength ... would you trust it? I certainly wouldn't.
I doubt it would meet any required anchorage standard either.
Paul Walbran

Crikey, I wouldn't trust just one of those either, thanks for posting the pictures.
Paul Hunt

When I got my '64 B it was fitted with static Securon belts, with only one of the two captive bolts being used. I changed these for the Britax inertia ones, but had to drill the mounting hole into the wheel arch fairly low down and near the rear panel to enable there to be enough room for the foldaway hood (grey frame) to still fit. If I'd put them higher up the wheelarch, the hood wouldn't fold down. I guess that does mean some risk of spinal compression in a shunt. That said, any shunt in a 50+ year old car probably won't be much fun..

The lower mounting fitted the captive bolt in the inner sill ok, the main difficulty was that, on my car at least, there is no captive bolt in the transmission tunnel mounting. I have long arms, but I can't reach round that far!!

Mike Winter

I'm about to fit a roll over bar, can I still use my inertia reel seatbelts?
c cummins

Provided they physically fit and don't interfere with the bar, why would they be any different?
Paul Walbran

This thread was discussed between 07/04/2015 and 08/05/2015

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